Third-trimester well-being scan and biophysical profile (BPP)

Medically written by Dr. Sushma Dhakal, MBBS · MD (Obstetrics & Gynaecology) · Fellowship in Fetal Medicine · Updated 30 October 2026 · 3 min read

In the last three months of pregnancy, a well-being scan checks that your baby is growing well and getting enough oxygen and nutrition from the placenta. It is not needed in every pregnancy, but it is very useful when there are risk factors or concerns.

What does a well-being scan check?

Growth: measurements of the head, abdomen and thigh bone give an estimated fetal weight, which is compared with growth charts and with earlier scans.
Amniotic fluid: measured as the deepest pool or the amniotic fluid index. Low fluid can be a sign that the placenta is not working as well as it should.
Placenta: its position (for example, whether it is low-lying) and appearance.
Presentation: whether the baby is head-down, breech or lying across.
Doppler: blood flow in the umbilical artery and, when needed, in the baby's brain (middle cerebral artery) shows how well the placenta is supporting the baby.

What is a biophysical profile (BPP)?

A BPP is a short, focused assessment of the baby's well-being. Over up to 30 minutes, the scan looks for four things, each scored 0 or 2:

breathing movements of the chest;
body or limb movements;
muscle tone (the baby opening and closing a hand or stretching and flexing);
a normal amount of amniotic fluid.

Often a CTG (non-stress test) of the baby's heart rate is added as a fifth part. A total of 8 or 10 out of 10 is reassuring. A lower score does not always mean a problem, as babies have sleep cycles, but it usually leads to repeat testing or a discussion about timing of delivery.

Who may need these scans?

A baby measuring small or large, or growth slowing on serial scans.
High blood pressure, pre-eclampsia, diabetes or other medical conditions.
Twins, a previous stillbirth or growth-restricted baby, or pregnancy beyond the due date.
Reduced fetal movements or bleeding in later pregnancy.

Reduced movements: do not wait

Get to know your baby's usual pattern of movements. If movements slow down, change or stop, contact your doctor or the hospital the same day. Do not wait until the next day and do not rely on home heartbeat devices. Prompt checking with CTG and scan is safe and quick.

Understanding the results

A normal well-being scan is reassuring for the near future, but it cannot predict everything, so your care continues as planned. If results are borderline, the scan is usually repeated within days or weeks. If they show the baby may be better off born, your team will discuss the safest timing and way of delivery with you.

Have questions about your pregnancy?

Book a consultation with Dr. Sushma Dhakal, Fellowship-trained fetal medicine specialist (FMF UK certified).

Book this scan Request Counselling

Frequently asked questions

What is a normal BPP score?

8 or 10 out of 10 is reassuring. Lower scores usually lead to repeat testing or closer monitoring.

Does every pregnancy need a third-trimester scan?

Not always. It is advised when there are risk factors such as growth concerns, high blood pressure, diabetes, twins or reduced movements.

What should I do if my baby moves less?

Contact your doctor or hospital the same day for a check. Do not wait until the next day.

Can the scan tell my baby's exact weight?

No. Estimated fetal weight can differ from the actual birth weight by about 10–15%.

This guide is for general information only and is not a substitute for personal medical advice. Every pregnancy is different. Please consult your doctor about your own situation. In an emergency, go to the nearest hospital.